A new botulinum toxin has emerged, and its discoverers are keeping its genetic identity a secret.

Scientists describe the toxin in two papers appearing in The Journal of Infectious Diseases, but they witheld full genetic details of the new bacterial strain that produces it to prevent people from developing the poison into a bioweapon. The decision mirrors the debate over whether to publish full details of work on the H5N1 bird flu.

The bacterium Clostridium botulinum produces toxins that cause botulism, a rare illness that can paralyze infected people. The toxins causing the illness are among the most poisonous substances identified to date. Scientists are concerned about releasing full details of the new bacterial strain and its toxin because there is currently no treatment against its effects.